Distal perfusion sheath

ABSTRACT

A distal perfusion sheath (DPS) is provided for cases where blood perfusion is needed for downstream arteries (distal) to the insertion point of the DPS within the target artery. The ability to provide distal perfusion with the DPS allows the DPS to be positioned in the target artery for long periods without causing lack of blood flow (ischemia) to an extremity that the target artery supplies. In embodiments, the DPS can still be used for surgical arterial access while allowing blood flow downstream.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of Non-provisionalApplication Ser. No. 13/548,458 filed Jul. 13, 2012 that claims prioritybenefit of U.S. Provisional Application Ser. No. 61/507,492, filed Jul.13, 2011 and U.S. Provisional Application Ser. No. 61/510,786, filedJul. 22, 2011; the contents of which are hereby incorporated byreference.

FIELD OF THE INVENTION

The present invention in general relates to arterial sheaths and methodfor surgical deployment thereof, and in particular to a vascular sheaththat facilitates blood perfusion to a distal artery thereby preventingischemia to the extremity the artery supplies.

BACKGROUND OF THE INVENTION

As endovascular procedures become more complicated, the procedures oftentake longer to perform and often require larger sheaths to be in apatient's arteries for extended periods of time. However, largersurgical sheaths impair blood flow to a distal extremity and can causeinjury to the nerves and muscles. In addition, after prolonged lack ofblood flow (ischemia) the extremity is at risk for re-perfusion injuryonce the sheath is removed that can increase muscle compartmentpressures (compartment syndrome), which can result in muscle necrosisand amputation.

Thus, there exists a need for a vascular surgical sheath that allowscontinued blood flow past the insertion point of the sheath, while thesheath is in place, to an extremity downstream to the sheath. Therefurther exists a need for a process for usage of such a sheath toinhibit compartment syndrome.

SUMMARY OF THE INVENTION

An inventive distal perfusion sheath (DPS) is provided for cases whereblood perfusion is needed for downstream arteries (distal) to theinsertion point of the DPS within the target artery. The ability toprovide distal perfusion with the DPS allows the DPS to be positioned inthe target artery for long periods without causing lack of blood flow(ischemia) to an extremity that the target artery supplies. In specificembodiments, the DPS is used for surgical arterial access while allowingblood flow downstream. In addition, embodiments of the DPS configuredwith longer perfusion shunts can allow a contra-lateral extremitydownstream to a large DPS to have blood flow while the sheath is inplace.

Embodiments of the DPS have at least 2 lumens, one for arterial accessand an outer expandable lumen for blood flow into the perfusion shunt.The outer lumen that feeds blood or other fluids is expanded once thesheath is in the artery. The outer lumen is expanded by injecting fluidinto scaffolding that expands the lumen. The outer lumen allows arterialblood to flow through a perfusion shunt that is attached to the externaldistal end of the sheath. The end of the perfusion shunt may then beinserted into an artery downstream (distal) to the sheath providingblood flow to the extremity. The insertion of the perfusion shunt can beaccomplished by making a small incision (arteriotomy) in the artery justbelow the sheath. The end of the perfusion shunt is then placed into theartery and secured with a vessel loop. The insertion of the perfusionshunt into a distal portion of the artery allows continued blood flowinto the artery downstream from the sheath. At the end of the surgicalprocedure the perfusion shunt is removed and the incision in the distalartery is repaired.

In an embodiment, in cases that require large specialized sheaths,downstream flow can be provided by placing a distal perfusion sheath inthe opposite extremity artery. The distal perfusion sheath can be smallenough to allow continued blood flow to the downstream extremity. Theperfusion shunt can then be inserted into the artery just below theopposite sheath to provide blood flow to the opposite extremity.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter that is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the invention are apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1A is a perspective view of an inventive distal perfusion sheath(DPS) device;

FIG. 1B is a longitudinal cross-sectional view of the device of FIG. 1Aalong line 1B-1B;

FIG. 1C is a cross-sectional view of the device of FIG. 1A along line1C-1C;

FIG. 1D is a cross-sectional view of an alternative device of FIG. 1Aalong line 1C-1C where the inner lumen for arterial access and an outerexpandable lumen are eccentric;

FIG. 2A is a perspective view of an artery prior to the insertion of asheath;

FIG. 2B is a perspective view of an artery with a conventional prior artsheath inserted, and the resultant impaired blood flow in the artery;

FIG. 2C is a perspective view of an artery with the inventive distalperfusion sheath inserted, prior to inflation of channels for distalperfusion;

FIG. 2D is a perspective view of an artery with the inventive distalperfusion sheath inserted, and the distal perfusion channels inflated toallow blood flow past the sheath;

FIG. 3 is a perspective view of an embodiment of an inventive distalperfusion sheath configured with multiple guidewires in the sheath;

FIGS. 4A-4D are a series of cross-sectional views of the device of FIG.3 along line 2-2 illustrating the unlocking and repositioning of aguidewire from amongst the three guidewires in the sheath:

FIG. 5 is a perspective view of an embodiment of an inventive distalperfusion sheath configured with an aperture in the sheath to allowblood flow downstream past the point of insertion in an artery;

FIG. 6 is a perspective view of an embodiment of an inventive distalperfusion sheath configured with a shunt tube in the sheath to allowblood flow downstream past the point of insertion in an artery;

FIG. 7 is a perspective view of an embodiment of an inventive distalperfusion sheath configured with vents in the form of a series or arrayof holes in the sheath to allow blood flow downstream past the point ofinsertion in an artery; and

FIG. 8 is a perspective view of the inventive distal perfusion sheath ofFIG. 7 inserted in an artery.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An inventive distal perfusion sheath (DPS) provides blood perfusion tothe artery downstream (distal) to the insertion point within the artery.The ability to provide distal perfusion with the DPS allows the DPS tobe positioned in the artery for long periods without causing lack ofblood flow (ischemia) to an extremity that the artery supplies. Inembodiments, the DPS can still be used for surgical arterial accesswhile allowing blood flow downstream. In addition, embodiments of theDPS configured with longer perfusion shunts can allow a contra-lateralextremity downstream to a large DPS to have blood flow while the sheathis in place.

Embodiments of the DPS have at least 2 lumens, one for arterial accessand an outer expandable lumen for blood flow into the perfusion shunt.The outer lumen that feeds blood or other fluids is expanded once thesheath is in the artery. The outer lumen is expanded by injecting fluidinto scaffolding that expands the lumen. The outer lumen allows arterialblood to flow through a perfusion shunt that is attached to the externaldistal end of the sheath. The end of the perfusion shunt may then beinserted into an artery downstream (distal) to the sheath providingblood flow to the extremity. The insertion of the perfusion shunt can beaccomplished by making a small incision (arteriotomy) in the artery justbelow the sheath. The end of the perfusion shunt is then placed into theartery and secured with a vessel loop. The insertion of the perfusionshunt into a distal portion of the artery allows continued blood flowinto the artery downstream from the sheath. At the end of the surgicalprocedure the perfusion shunt is removed and the incision in the distalartery is repaired.

In a specific embodiment, in cases that require large specializedsheaths, downstream flow can be provided by placing a distal perfusionsheath in the opposite extremity artery. The distal perfusion sheath canbe small enough to allow continued blood flow to the downstreamextremity. The perfusion shunt can then be inserted into the artery justbelow the opposite sheath to provide blood flow to the oppositeextremity. The inventive sheath is readily constructed withbiocompatible polyurethane materials, with possible metal, or Nitinolreinforcement. It is appreciated that an inventive sheath optionally andreadily incorporates substances such as radio opaque marking compoundson the catheter for accurate positioning such as barium sulfate; slipagents for smooth artery entry such as hydrophilic gels sold under thattradename GLIDEX®; anticoagulants such as heparin; sustained releasedrugs such as antibiotics and plaque formation inhibitors; andcombinations thereof.

Referring now to FIGS. 1 and 2, an inventive distal perfusion sheath(DPS) is depicted generally at 10. The DPS 10 includes an inner lumen 12for arterial access and an outer expandable lumen 14 for blood flow intothe perfusion shunt 24. The outer lumen 14 is expanded following theinsertion of the DPS 10 into an artery V (FIGS. 2A, 2C, and 2D) byinjecting fluid through port 20 with control valve 22 to inflatescaffolds 26 as depicted in FIGS. 1B, 1C, 1D, and 2D. FIG. 1C is across-sectional view of the device of FIG. 1A along line 1C-1C where theinner lumen 12 for arterial access and an outer expandable lumen 14 areconcentric with the scaffolds 26 evenly distributed along thecircumference of the inner lumen 12. FIG. 1D is a cross-sectional viewof the device of FIG. 1A along line 1C-1C where the inner lumen 12 forarterial access and an outer expandable lumen 14 are not concentric withthe scaffolds 26 positioned primarily to one side. The scaffolds 26,which do not obstruct blood flow, expand the outer lumen 14 until theouter dimensions of outer lumen 14 contact the inner diameter of theartery V, regardless of whether a concentric or eccentric embodiment isin usage. Hemostatic port 16 controls blood flow in the inner lumen 12,and allows for insertion of a catheter, guide wire, camera, or othersurgical device into the artery V. Flush port 18 controls fluids in theinner lumen 12. While the inner lumen 12 and outer lumen 14 are depictedas being concentric in FIG. 1C, it is appreciated that asymmetricplacement or expansion of scaffolds 26 affords an eccentric arrangementof inner lumen 12 and outer lumen 14, as shown in FIG. 1D, where likenumeral have the meanings previously ascribed thereto.

FIG. 2A depicts an artery V prior to the insertion of a sheath. Prior tothe insertion of a sheath blood flow 32 is relatively unimpeded fromproximal end A to distal end B. In FIG. 2B, a conventional sheath 34 isinserted in artery V with a resultant impairment of blood or fluid flow32 from proximal end A to distal end B. In a similar manner in FIG. 2C,an embodiment of the DPS 10, with the perfusion shunt 24 not deployed,is inserted into artery V with an impairment of blood flow 32 fromproximal end A to distal end B. However, as shown in FIG. 2D with theopening of the outer lumen 14 blood flow 32 commences from proximal endA to distal end B through perfusion shunt 24, the perfusion shunt 24inserted into the distal portion of artery V through incision 28. Thusas shown in FIG. 2D with the DPS 10 fully deployed (outer lumen 14 open)and perfusion shunt 24 inserted in the distal portion of artery V, bloodflow is rerouted beyond the DPS 10.

FIGS. 3 and 4A-4D illustrate an embodiment of a distal perfusion sheath(DPS) 40 employing multiple guidewires (42 a, 42 b, 42 c) forimplementations where simultaneous guidewire access to multiple targetarteries is required without disrupting blood flow to a distal bodilyextremity that the artery supplies. An engagement system (44 a, 44 b, 44c) independently secures the one or more guidewires within the sheath ofthe DPS 40 to maintain the separate positions of the guidewires. Theengagement system (44 a, 44 b, 44 c) is a series of wire-lock engagementpoints (44 a, 44 b, 44 c) positioned along for example, thecircumference of an inventive sheath. Selection of a guidewire is madewith a rotating hub 46 with a hemostatic port 16 at the center.

In operation, the rotation of the hub 46 at the distal end of the DPSallows the slit 48 of the hemostatic port 16 to line up with a desiredwire-lock (44 a, 44 b, 44 c) of the engagement system to allow theguidewire to be positioned in and out of the wire-lock. When the lockedguidewire is to be used in the main sheath lumen or inner lumen 12 ofthe DPS 40, the hub 46 is rotated to line up the valve-slit with theguidewire in the wire-lock. The lock is opened releasing the guidewirewhich is then moved through the valve-slit to the center hub of thehemostatic valve and then used in a conventional manner in a targetartery. Following the usage of the unlocked guidewire, the guidewire isreturned through the valve-slit to the wire-lock to be reengaged. Thewire-lock when closed secures the guidewire in place preventing it frombeing dislodged while the main inner lumen 12 of the sheath is used withother guidewires. The hub 46 may then be rotated to line up thevalve-slit 48 with another wire-lock to access a different guidewire forserving the same or different target artery.

FIGS. 4A-4D are a series of cross-sectional views of the DPS device 40of FIG. 3 along line 2-2 illustrating the unlocking and repositioning ofthe guidewire 42 b. In FIG. 2A, all three of the guidewires (42 a, 42 b,42 c) are secured or locked to the engagement system (44 a, 44 b, 44 c).In FIG. 2B, the rotating hub 46, which is free to rotate eitherclockwise or counter-clockwise as indicated by the bidirectional arrow50, is rotated to position the slit 48 to line up with engagement 44 b,and the guidewire 42 b is unlocked from engagement 44 b and moved inwardtoward the hemostatic valve seal port 16 in the center of the rotatinghub 46. In FIG. 2C, the guidewire 42 b is now positioned within thehemostatic valve seal port 16, and the guidewire is now free to moveback and forth, or be twisted, along the longitudinal axis C-C of DPSdevice 40. In FIG. 2D, the guidewire 42 b is returned to engagement 44b, and locked in place. The rotating hub 46 and corresponding slit 48are now free to be rotated to another of the engagement 44 a or 44 c forusing guidewires 42 a or 42 c, respectively.

FIG. 5 is a perspective view of an embodiment of an inventive distalperfusion sheath 60 configured with an aperture 62 in the outer wall 64extending to the sheath lumen 66 of the inserted portion 68 of thedistal perfusion sheath 60 to allow blood flow 32 downstream past thepoint of insertion 70 in an artery V. The distal perfusion sheath 60minimizes the impairment of blood flow 32 in the artery V, without theneed for a second incision in the artery V for a shunt, such as for theperfusion shunt 24 of FIG. 2D or FIG. 3. Hemostatic port 72 controlsblood flow in the sheath lumen 66, and allows for insertion of acatheter, guide wire, camera, or other surgical device into the arteryV.

The distal perfusion sheath 60 is readily constructed with biocompatiblepolyurethane materials, with possible metal, or Nitinol reinforcement.It is appreciated that an inventive sheath optionally and readilyincorporates substances such as radio opaque marking compounds on thecatheter for accurate positioning such as barium sulfate; slip agentsfor smooth artery entry such as hydrophilic gels sold under thattradename GLIDEX®; anticoagulants such as heparin; sustained releasedrugs such as antibiotics and plaque formation inhibitors; andcombinations thereof. It is noted that a single guidewire or multipleguidewires as shown in FIGS. 3 and 4A-4D may be used with the distalperfusion sheath 60 for implementations where simultaneous guidewireaccess to multiple target arteries is required without disrupting bloodflow to a distal bodily extremity that the artery supplies.

FIG. 6 is a perspective view of an embodiment of an inventive distalperfusion sheath 80 configured with a shunt tube 82 in fluidcommunication with the sheath lumen 84, the shunt tube 82 extending fromthe inserted portion 86 of the distal perfusion sheath 80 to allow bloodflow downstream past the point of insertion 88 in an artery. The distalperfusion sheath 80 minimizes the impairment of blood flow 32 in theartery V, without the need for a second incision in the artery V for ashunt, such as for the perfusion shunt 24 of FIG. 2D or FIG. 3.Hemostatic port 89 controls blood flow in the sheath lumen 84, andallows for insertion of a catheter, guide wire, camera, or othersurgical device into the artery V.

The distal perfusion sheath 80 is readily constructed with biocompatiblepolyurethane materials, with possible metal, or Nitinol reinforcement.It is appreciated that an inventive sheath optionally and readilyincorporates substances such as radio opaque marking compounds on thecatheter for accurate positioning such as barium sulfate; slip agentsfor smooth artery entry such as hydrophilic gels sold under thattradename GLIDEX®; anticoagulants such as heparin; sustained releasedrugs such as antibiotics and plaque formation inhibitors; andcombinations thereof. It is noted that a single guidewire or multipleguidewires as shown in FIGS. 3 and 4A-4D may be used with the distalperfusion sheath 80 for implementations where simultaneous guidewireaccess to multiple target arteries is required without disrupting bloodflow to a distal bodily extremity that the artery supplies.

FIGS. 7 and 8 are perspective views of an embodiment of an inventivedistal perfusion sheath 90 configured with a vent 92 in the form of aseries or an array of holes in the outer wall 94 extending to the sheathlumen 102 of the distal perfusion sheath (DPS) 90 to allow blood flow 32downstream past the point of insertion 104 in an artery V. Thearrangement of the small holes in the series or array of holes that makeup the vent 92 prevent inadvertent placement of a guidewires (J-tip) inthe wrong direction out of the sheath 90 in the artery V. The distalperfusion sheath 90 minimizes the impairment of blood flow 32 in theartery V, without the need for a second incision in the artery V for ashunt, such as for the perfusion shunt 24 of FIG. 2D or FIG. 3. Thesheath 90 may be placed by cut-down or percutaneous into a patient'sartery.

In order to stabilize the sheath 90 in position, a dilated portion ofthe sheath above the vents forms a sheath anchor 96 that acts to securethe sheath in an intended position. The sheath anchor 96 is proximate tothe insertion point 104, and keeps the distal perfusion sheath 90intravascular. The placement and maintaining the position of the DPS 90is critical, and if the vents 92 are positioned outside the artery,significant blood loss may occur. Additionally, the sheath anchor 96prevents movement of the sheath 90 when passing guidewires and cathetersthat may displace the sheath 90 repositioning the vents 92extravascular. The sheath anchor 96 widens when the sheath 90 isintravascular, and the blood pressure deploys the sheath anchor bladder96 around the sheath 90. The widening of the sheath anchor 96 securesthe vented part of the sheath intravascular preventing bleeding from anextravascular vent position. The valve 100 is used to deflate the sheathanchor bladder 96 for removal of the sheath 90.

A sheath depth indicator 98 provides feedback for the proper placementof the distal perfusion sheath 90. During initial placement of thesheath 90, when the sheath 90 is inserted in the artery up to theinternal end 981 of the indicator 98 blood will begin to come out theexternal indicator port 98E. The exiting blood from external indicatorport 98E shows the user that the proper insertion depth for the sheath90 has been arrived at, and that the distal perfusion vents 92 andanchor 96 are intravascular. The sheath depth indicator 98 provides forpercutaneous sheath placement. Hemostatic port 106 controls blood flowin the sheath lumen 102, and allows for insertion of a catheter, guidewire, camera, or other surgical device into the artery V.

The distal perfusion sheath 90 with vents 92 is readily constructed withbiocompatible polyurethane materials, with possible metal, or Nitinolreinforcement. It is appreciated that an inventive sheath optionally andreadily incorporates substances such as radio opaque marking compoundson the catheter for accurate positioning such as barium sulfate; slipagents for smooth artery entry such as hydrophilic gels sold under thattradename GLIDEX®; anticoagulants such as heparin; sustained releasedrugs such as antibiotics and plaque formation inhibitors; andcombinations thereof. It is noted that a single guidewire or multipleguidewires as shown in FIGS. 3 and 4A-4D may be used with the distalperfusion sheath 90 for implementations where simultaneous guidewireaccess to multiple target arteries is required without disrupting bloodflow to a distal bodily extremity that the artery supplies.

The foregoing description is illustrative of particular embodiments ofthe invention, but is not meant to be a limitation upon the practicethereof. The following claims, including all equivalents thereof, areintended to define the scope of the invention.

The invention claimed is:
 1. A sheath for insertion into an artery, saidsheath comprising: an inner lumen; an outer lumen encapsulating saidinner lumen; scaffolds joining said inner lumen and said outer lumen; ashunt tube in fluid communication with said outer lumen, said shunt tubeextending from an inserted portion of said sheath into the artery toallow blood flow to a distal portion of the artery downstream of a pointof insertion of said sheath into said artery; wherein said outer lumenis expandable; and a hemostatic port sealing said inner lumen, saidhemostatic port controlling blood flow in said inner lumen, and isconfigured to accept at least one of: a catheter, a guide wire, or acamera.
 2. The sheath of claim 1 further comprising at least one of thecatheter, the guide wire, or the camera entering said inner lumen and influid communication with the artery.
 3. The sheath of claim 1 whereinsaid outer lumen has a vent therein.
 4. The sheath of claim 1 furthercomprising the guidewire within said lumen to afford simultaneousguidewire access to a target artery without disrupting blood flow to thedistal portion of the artery.
 5. The sheath of claim 1 furthercomprising: a series of scaffolds distributed along the circumference ofsaid inner lumen and supporting an outer wall that defines said outerlumen; and an injection port with a control valve in fluid communicationwith said series of scaffolds, where said injection port introduces afluid to expand said series of scaffolds.
 6. The sheath of claim 5wherein said inner lumen and said outer lumen are concentric, where saidseries of scaffolds are evenly distributed along the circumference ofsaid inner lumen.
 7. The sheath of claim 5 wherein said inner lumen andsaid outer lumen are ecentric, where said series of scaffolds arepositioned primarily to one side of said inner lumen.